Even though he says, "I'm the worst with my memory banks, about as bad as you can get," Mac Rebennack remembers "the shift" that allowed him to become one with his onstage persona — the charismatic, extravagantly costumed, voodoo-preaching rock star known as Dr. John.

"It kind of came down to about the time, I think it was a record that was called, it was 'Gumbo,' " Rebennack/Dr. John says of his hit 1972 album during a discursive, 40-minute conversation that reveals the Rock and Roll Hall of Famer to be candid and evasive, prickly and gracious, weary and wise, and conveying it all through his feral N'Awlins diction and self-styled vocabulary. "Where we used to store all the costumes and stuff, it all got burned up. ... To be frank with you, I took that insurance money and spent it on some other things. It was just somewhere around all of that. It was happening. But that shoved it in some more different directions. ... I think I was really into that shift when we did a record [in 1975] called 'Hollywood Be Thy Name,' because I was presenting a show, and I had a lot of people on the show, and I think that was the time when I really got locked into, 'Hey, well, I could be loose with this either way.' "

Dr. John, who will appear this Saturday at the Sunshine Blues Festival in Boca Raton, has shifted several times since then. In 1989, during another of his many trips to rehab for drug addiction, something finally clicked. He emerged clean and sober, and says he has been to this day. In 1994, he came clean in another way, with the eye-popping autobiography "Under a Hoodoo Moon." And in 2012, he shifted once more, with the release of "Locked Down," a vigorous album produced by the Black Keys' Dan Auerbach, who reportedly pressed the 72-year-old to write more from the perspective of Mac Rebennack and less from the point of view of the self-anointed Gris-Gris Man, Dr. John. Instead, the musician brought both of his personas to the recording session, though he maintains that there no longer is a difference between the two.

A confessional but defiant work, "Locked Down" finds Rebennack reflecting on his illicit exploits (the title track, "Big Shot"), celebrating his spiritual wanderings ("Eleggua," "God's Sure Good"), decrying the general state of things ("Revolution," "You Lie") and making amends ("My Children, My Angels"). It's a soul-baring effort from a man who makes no excuses for his past, and who says he has little want for nostalgia.

"Actually, I try not to think back too much," Rebennack says. "Even though I do it at times, I can remember what I remember today. But there's a lot of stuff that I don't need to remember. Some of it was just — the life I was living dictated too much mess to it. It's just not worth it, you know, to get caught up in some of that stuff.

"Listen, I don't have no regrets," he continues. "And I don't have no, like, sick feelings about anything. You know what? One of the things that I truly believe is that we learn stuff. We learn how to follow paths, and we learn how to do things. There ain't no street signs in the jungle we call life. So you got to know where your path is at. And if you don't follow that path, you're going to take some detours that could get you killed and could get you hurt. And believe me, I took a lot of them detours. I don't want to take some detours again. I want to just stay on the path. Keep it simple. And that's what I'm working on. Just for the day."

Derek Trucks, the 33-year-old blues-rock guitarist and former child prodigy who will headline the Sunshine Blues Festival with the Tedeschi Trucks Band, fronted by his wife, the singer-guitarist Susan Tedeschi, appeared on Dr. John's 2010 album, "Tribal." Trucks says the festival's organizers asked him and Tedeschi to provide a wish list of artists they'd like to see at the event, and the couple immediately suggested Dr. John.

"One of the things I've always appreciated about him is there's a fearlessness to the way he makes records," Trucks says. "Some of them are just weird as sh--. And you can tell there's nobody telling him what to do. To me, that's the mark of a true artist. There's not a lot of people who have a singular vision and are hardheaded enough to carry it through."

Auerbach certainly wasn't foolish enough to cloud that vision, though most of the songs on "Locked Down" wouldn't sound out of place on one of the Black Keys' recent albums. "Locked Down" is undeniably funky, but it's hardly loose. Auerbach, who's become something of an in-demand roots-rock producer, has developed an identifiable production style: airtight, multitracked recordings that abide no false note yet manage to sound as if they were captured in one take.

Rebennack, who was unfamiliar with Auerbach or the Black Keys when the younger musician sought him out in New Orleans with the idea of working together, says he appreciates the way Auerbach made him look at his music from a new perspective, or, as he puts it, "perspect."

"I just like Dan, the way he operates, and the way he thinks," Rebennack says. "I really grew to get, like, a different picture from him, that I liked. He's a very interesting cat. And that's a good thing.

"Life is always connected in different weird ways with musicians and musical things," he says later in the interview. "Sometimes, I'm one of them people, I don't like to get caught up in nothing, I just want to feel free and easy. And if I don't feel free and easy, I don't want to feel cheap and greasy. That's just personable feelings."